C++/CLI wrapper for native C++ to use as reference in C#

Haix64 picture Haix64 · Apr 19, 2012 · Viewed 37.5k times · Source

Title explains. I have native C++ dlls that I'm writing C++/CLI wrappers for, which will in turn will be imported in C# as reference.

The problem is that in C# I don't see the classes I have in wrapper (imported from DLL).

What keywords should I use and HOW to re-declare my native C++ objects to become visible in C#?

Answer

Asik picture Asik · Apr 19, 2012

Ok, tutorial. You have a C++ class NativeClass that you want to expose to C#.

class NativeClass { 
public:
    void Method();
};

1) Create a C++/CLI project. Link to your C++ library and headers.

2) Create a wrapper class that exposes the methods you want. Example:

#include "NativeClass.h"

public ref class NativeClassWrapper {
    NativeClass* m_nativeClass;

public:
    NativeClassWrapper() { m_nativeClass = new NativeClass(); }
    ~NativeClassWrapper() { this->!NativeClassWrapper(); }
    !NativeClassWrapper() { delete m_nativeClass; }
    void Method() {
        m_nativeClass->Method();
    }
};

3) Add a reference to your C++/CLI project in your C# project.

4) Use the wrapper type within a using statement:

using (var nativeObject = new NativeClassWrapper()) {
    nativeObject.Method();
}

The using statement ensures Dispose() is called, which immediately runs the destructor and destroys the native object. You will otherwise have memory leaks and probably will die horribly (not you, the program). Note : The Dispose() method is magically created for you.